The physical and mental benefits of exercise are widely known but seldom available to persons suffering from Alzheimer's disease (AD). This article presents information on the potential benefits of physical exercise for people with AD, discussing some of the metabolic and neuropathological changes regarded as underlying causes of AD, as well as some of the psychological and organic abnormalities that can be modified through exercise. The extent to which physical exercise programs can play a role in the treatment of AD is addressed in the second part of the article, describing the most relevant clinical studies in this field. Finally, the article provides information about how to prescribe physical exercise for AD patients, mainly by giving examples of structured physical programs designed for older adults with dementia.